Internet Engineering Task Force (IETF) D. Eastlake 3rd
Request for Comments: 6327 Huawei
Updates: 6325 R. Perlman
Category: Standards Track Intel Labs
ISSN: 2070-1721 A. Ghanwani
Brocade
D. Dutt
Cisco Systems
V. Manral
Hewlett Packard Co.
July 2011
Routing Bridges (RBridges): Adjacency
Abstract
The IETF TRILL (TRansparent Interconnection of Lots of Links)
protocol provides optimal pair-wise data forwarding without
configuration, safe forwarding even during periods of temporary
loops, and support for multipathing of both unicast and multicast
traffic. TRILL accomplishes this by using IS-IS (Intermediate System
to Intermediate System) link state routing and by encapsulating
traffic using a header that includes a hop count. Devices that
implement TRILL are called Routing Bridges (RBridges).
TRILL supports multi-access LAN (Local Area Network) links that can
have multiple end stations and RBridges attached. This document
describes four aspects of the TRILL LAN Hello protocol used on such
links, particularly adjacency, designated RBridge selection, and MTU
(Maximum Transmission Unit) and pseudonode procedures, with state
machines. There is no change for IS-IS point-to-point Hellos used on
links configured as point-to-point in TRILL.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6327.
Perlman, et al. Standards Track [Page 1]RFC 6327 RBridges: Adjacency July 2011Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
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Perlman, et al. Standards Track [Page 2]RFC 6327 RBridges: Adjacency July 2011Table of Contents
1. Introduction ....................................................4
1.1. Content and Precedence .....................................4
1.2. Terminology and Acronyms ...................................5
2. The TRILL Hello Environment and Purposes ........................5
2.1. Incrementally Replacing 802.1Q-2005 Bridges ................5
2.2. Handling Native Frames .....................................6
2.3. Zero or Minimal Configuration ..............................7
2.4. MTU Robustness .............................................7
2.5. Purposes of the TRILL Hello Protocol .......................8
3. Adjacency State Machinery .......................................9
3.1. TRILL LAN Hellos, MTU Test, and VLANs ......................9
3.2. Adjacency Table Entries and States ........................10
3.3. Adjacency and Hello Events ................................11
3.4. Adjacency State Diagram and Table .........................13
3.5. Multiple Parallel Links ...................................14
3.6. Insufficient Space in Adjacency Table .....................15
4. RBridge LAN Ports and DRB State ................................15
4.1. Port Table Entries and DRB Election State .................16
4.2. DRB Election Events .......................................16